Apparatus for controlling the tension of webs

ABSTRACT

A mandrel for regulating the tension on a web being unrolled from a storage roll placed on the mandrel by changing the friction force between the storage roll which rotates relative to the mandrel. The mandrel is radially expandable and comprises a split cylindrical sleeve housing a radially expandable spring. The spring is expanded by means of a rotatable stud adjacent one end of the spring, a stud fixed to the sleeve on the other end of the spring and a screw fixed to the rotatable stud and mating with a spiral bore in the fixed stud. During use, one side of the sleeve adjacent the opening is fixed while the other side of the sleeve adjacent the opening is free.

Unite States Patent [191 OBrien [54] APPARATUS FOR CONTROLLING THE TENSION OF WEBS [76] Inventor: Raymond W. OBrien, Cedar Road,

Boxford, Mass. 01921 [22] Filed: Feb. 8, 1971 [21] Appl. No.: 113,538

[52] US. Cl ..242/72, 279/2 [51] Int. Cl. ..B65h 75/24 [58] Field of Search 242/68, 72, 72.1, 46.6, 46.7,

[56] References Cited v UNITED STATES PATENTS 1 Jan. 23, 1973 Primary ExaminerGeorge F. Mautz Assistant Examiner Edward J. McCarthy Att0rney-Kenway, Jenney & Hildreth [57] ABSTRACT A mandrel for regulating the tension on a web being unrolled from a storage roll placed on the mandrel by changing the friction force between the storage roll which rotates relative to the mandrel. The mandrel is radially expandable and comprises a split cylindrical sleeve housing a radially expandable spring. The spring is expanded by means of a rotatable stud adjacent one end of the spring, a stud fixed to the sleeve on the other end of the spring and a screw fixed to the rotatable stud and mating with a spiral bore in the fixed stud. During use, one side of the sleeve adjacent the opening is fixed while the other side of the sleeve adjacent the opening is free.

4 Claims, 3 Drawing Figures PATENTEDJAN23 I975 SHEET 1 OF 2 3,712,555

INVENTOR RAYMOND W. O'BRIEN ATTORNEYS APPARATUS FOR CONTROLLING THE TENSION OF WEBS This invention relates to a radially adjustable mandrel adapted to fit within a storage roll for web materials.

Generally, when it is desired to cover elongated constructions such as conduits or cables with a web material, the web is unwound from a storage roll placed on a stationary mandrel that is radially adjustable to adjust the frictional force between the mandrel and the rotating storage roll and the tension on the web being unwound and wrapped on the elongated construction. The tension on the web depends upon the type of web employed and the construction being wrapped and it is essential that the tension on the web be maintained within close tolerances during the wrapping operation to attain a tight-fitting wrap without utilizing excessive quantities of the web. Thus, it is desirable that the mandrel be adjustable so that the friction between the mandrel and the storage roll is likewise adjustable to eliminate the need for having a large number of mandrels on hand to accommodate all types of webs and constructions to be wrapped. Furthermore, it is'desirable that the mandrel be adjustable to attain fine adjustments on the tension on the web and that a means for making the adjustments can be effected without removing the storage roll from the mandrel.

The present invention provides a radially adjustable mandrel comprising an expandable cylindrical sleeve which houses a spring and a means for expanding or compressing the spring. The spring is expandable in a direction perpendicular to the axis of the sleeve thereby being capable of exerting an adjustable force on the sleeve. The diameter of the sleevedepends upon the force exerted on it by the spring and, thus, the frictional force between the sleeve and a roll stored on the sleeve, and the tension on a web being unrolled from the roll aredependent upon the radius of the spring.

The invention will be more fully described with reference to the accompanying drawings.

FIG. 1 is an exploded isometric view, in partial cross section, of the mandrel of this invention.

FIG. 2 isan isometric view of the portion of the mandrel within the sleeve.

FIG. 3 is an isometric view of the mandrel in use in a winding apparatus.

Referring to FIG. 1, the mandrel, generally indicated at 1, comprises a flexible split cylindrical sleeve 2 having an opening 3 which extends along its entire length. The sleeve 2 is attachedon one side 9 of the opening 3 to the periphery of studs 5 and'6 by means of screws 4 through bores 7 while the opposing side 8 of thesleeve 2 remains unattachedso that it is free to move relative to the studs 5 and 6. The sleeve 2 is also attached to the studs 5 and 6 by means of screws 4a through bores 70 which are located approximately 160 180 from the secured side 9.- The attachments with screws 4a are needed to attain the desired sleeve expansion. The stud 5 has a central bore'll for receiving screw 12 which is fixedly attached at its opposing end to compression stud 13. The direction of rotation of a storage roll placed on sleeve 2 is alwaysaway from the side fixed to the studs 5 and 6. Thus, when the sleeve 2 is attached to the studs 5 and 6 in the manner shown in FIG. 1, a storage roller (not shown) will be rotated in the clockwise direction.

The stud 6 may be a cylindrical piece or may be modified to have a spring-loaded latch 14 which prevents a rotating storage roller from slipping off the mandrel. One end of the latch 14 is retained in opening 15 by means of a screw 16 so that the rotation of a storage roller on the mandrel will be toward the fixed end of the latch. When it is desired to rotate a storage roller in the counterclockwise direction, the opposite end of the latch will be fixed in the opening 15 by means of a screw which is inserted into bore 18 and the end adjacent the bore associated with screw 16 will be free. The free end of the latch contacts a spring in the opening 15 so that its equilibrium position is radially outward from the stud 6. Stud 6 is provided with a central bore 19 that extends through its length to permit access to compression stud 13. The expandable spring 23 rests on shoulder 20 of stud 5 and on shoulder 21 of stud 13. The relative compression of spring 23 is controlled by turning compression stud 13 and screw 12 which stud 5 is fixed relative to sleeve 2. Screw 12 will progress into bore 11 thereby causing spring 23 to expand radially. Conversely, when compression stud 13 is turned counterclockwise, screw 12 will be removed from bore 11 and the compression on spring 23 will be decreased thereby decreasing its diameter.

Referring to FIG. 3, a web is spirally wound on storage roller 31 which in turn is placed on mandrel l. The tension on the web 30 at area 32 after it has been unrolled from storage roller 31 is regulated as described above. A roller assembly 33 is provided to direct the web 30 into the web folder 34. The rollers 35 and 36 are attached to arms 37 and 38 and are pivotable around axle 39. When under tension, the web 30 is passed under roller 35, over roller 36 and into folder 34 wherein the edges of the web 30 are folded underneath the moving web 30. The web 30 passes over roller 40 and is wound around conduit 40 to form a covering 41 thereon by rotating circular plate 42 to which is attached the entire assembly.

While the present invention has been described with reference to the mandrel shown in the drawings it is to be understood that other equivalent means for fixing one side of theexpandable cylinder while expanding the spring can be employed, thus, the expandable cylinder can-be attached to the rotating housing by adding an appropriate flange to the cylinder so long as the housing has a bore for accommodating the screw 12.

I claim:

I. A radiallyexpandable mandrel comprising a cylindrical sleeve split longitudinally along its entire length forming a continuous opening with opposed sides, means fixing one of said sides to prevent movement thereof, the other of said sides being freely movable, a radially expandable spring within said sleeve having a diameter sufficiently large to contact the inside surface of the cylindrical sleeve, means for compressing said spring axially to expand said sleeve radially and move said freely movable side radially outward.

2. The mandrel of claim 1 wherein the means for compressing said spring comprises a rotatable stud adjacent one end of said spring, a second stud fixed to one side of the openingof said cylindrical sleeve adjacent the secondend of said spring and a screw fixedly attached to said rotatable stud and matingwith a spiral bore in said second stud.

ble stud attached to said cylinder on the same side of said opening as said second stud.

4. The mandrel of claim 3 wherein the third stud has means for preventing a storage roll placed on said sleeve from being removed from said sleeve. 

1. A radially expandable mandrel comprising a cylindrical sleeve split longitudinally along its entire length forming a continuous opening with opposed sides, means fixing one of said sides to prevent movement thereof, the other of said sides being freely movable, a radially expandable spring within said sleeve having a diameter sufficiently large to contact the inside surface of the cylindrical sleeve, means for compressing said spring axially to expand said sleeve radially and move said freely movable side radially outward.
 2. The mandrel of claim 1 wherein the means for compressing said spring comprises a rotatable stud adjacent one end of said spring, a second stud fixed to one side of the opening of said cylindrical sleeve adjacent the second end of said spring and a screw fixedly attached to said rotatable stud and mating with a spiral bore in said second stud.
 3. The mandrel of claim 1 wherein the means for compressing said sprinG comprises a rotatable stud adjacent one end of said spring, a second stud fixed to one side of the opening of said cylindrical sleeve adjacent the second end of said spring, a screw fixedly attached to said rotatable stud and mating with a spiral bore in said second stud and a third stud adjacent said rotatable stud attached to said cylinder on the same side of said opening as said second stud.
 4. The mandrel of claim 3 wherein the third stud has means for preventing a storage roll placed on said sleeve from being removed from said sleeve. 